Printing apparatus for adjusting width of object and printing method

ABSTRACT

A printing apparatus includes a reception unit that receives outline information representing an outline of a character, a generation unit that generates, using the outline information, a bitmap including pixels corresponding to the character, the pixels being associated with a graphic attribute, a changing unit that refers an attribute associated with a pixel adjacent to one of the pixels corresponding to the character, and changes a density value of the adjacent pixel associated with the referred attribute being different from a graphic attribute and a character attribute to a density which is based on a density value of the one pixel, and a printing unit that prints an image based on the bitmap after the change.

BACKGROUND

Field

The present disclosure relates to a technique for adjusting the width ofan object.

Description of the Related Art

There is a demand for changing the image quality of an image to beprinted, such as the thickness of thin lines and texts, based on user'spreferences. For example, there are demands for a clear output thickerthan normal and an output for faithfully reproducing electronic data. Insome cases, a user normally using thick fonts demands an output of thintexts to avoid text blurring. Japanese Patent Application Laid-Open No.2012-121265 discusses a technique for adjusting the width of a text (anobject having a text attribute) output from an application. JapanesePatent Application Laid-Open No. 2012-121265 discusses a technique forfinding a boundary at which an object having a text attribute isadjacent to an object having another attribute and expanding the objecthaving a text attribute toward the object having the other attribute atthe boundary.

A recent application outlines (graphically defines) a text and thensends the outlined text to a printer or a printer driver. Since anoutlined text is handled as an object having a graphic attribute, theconventional technique is able to thicken a text object having a textattribute, but is unable to thicken a text object having a graphicattribute.

SUMMARY

Embodiments are directed to provision of a method for adjusting thewidth of an outlined text.

According to an aspect of the embodiments, a printing apparatus includesa reception unit configured to receive outline information representingan outline of a character, a generation unit configured to generate,using the outline information, a bitmap including pixels correspondingto the character, the pixels being associated with a graphic attribute,a changing unit configured to refer an attribute associated with a pixeladjacent to one of the pixels corresponding to the character, and tochange a density value of the adjacent pixel associated with thereferred attribute being different from a graphic attribute and acharacter attribute to a density which is based on a density value ofthe one pixel, and a printing unit configured to print an image based onthe bitmap after the change.

Further features will become apparent from the following description ofexemplary embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram schematically illustrating an image formingapparatus.

FIG. 2 illustrates example types of attributes.

FIGS. 3A, 3B, and 3C illustrate advantages of correcting attributes.

FIG. 4 illustrates an effect of smoothing processing.

FIGS. 5A and 5B illustrate thickening processing.

FIGS. 6A and 6B illustrate user interfaces (UIs) for setting thickeningprocessing.

FIG. 7 is a flowchart illustrating thickening processing.

FIG. 8 illustrates an outlined text in a graphic.

FIG. 9 illustrates an attribute correction unit according to a thirdexemplary embodiment.

FIGS. 10A, 10B, and 10C illustrate processing windows including a targetpixel and at least one reference pixel.

DESCRIPTION OF THE EMBODIMENTS

Image processing in an image forming apparatus discussed in the presentspecification will be described in detail below with reference to theaccompanying drawings.

FIG. 1 is a system block diagram illustrating an image forming apparatusaccording to a first exemplary embodiment. Although, according to thepresent exemplary embodiment, a multifunction peripheral provided with ascanner and a printer as an image forming apparatus is assumed, not onlya multifunction peripheral but also other printing devices such as asingle functional printer and the like can be used.

The structure of the image forming apparatus according to the presentexemplary embodiment will be described below.

As illustrated in FIG. 1, the image forming apparatus includes a centralprocessing unit (CPU) 16 including at least one processor, a randomaccess memory (RAM), a read only memory (ROM), and a hard disk unit(HDD) as a storage unit 15. The image forming apparatus is also providedwith a scanner as an image reading unit 10, a network interface card asan image reception unit 11, a touch screen as a user interface (UI) unit17, a large-scale integration (LSI) (image processing circuit) as animage processing unit 12, and a printer as an image output unit 13. Theimage forming apparatus is connected with an external apparatus such asa server for managing image data and a personal computer (PC) forinstructing the image forming apparatus to perform printing via anexternal communication channel 14 such as a local area network (LAN) andthe Internet.

Functions of each component of the image forming apparatus illustratedin FIG. 1 will be described below.

The RAM as the storage unit 15 is used as an area for storing data andvarious types of information and also used as a work area for the CPU16. The ROM is used as an area for storing various control programs. TheHDD is used to temporarily store data received by the image receptionunit 11 from an external apparatus and data that has undergone imageprocessing by the image processing unit 12.

The CPU 16 controls each component according to a program stored in theROM.

The image reading unit 10 reads an image of a document. For example, theimage reading unit 10 reads read, green, and blue (RGB) bitmap imagedata on a document. Then, the read RGB image is sent to the imageprocessing unit 12 (a scanner image processing unit 120).

The image reception unit 11 receives image data (Page DescriptionLanguage (PDL) data) described in a PDL received from an externalapparatus via a network. The received PDL data is sent to the imageprocessing unit 12 (a printer image processing unit 121).

The image processing unit 12 performs image processing on the receivedimage data and sends the processed image data to the image output unit13.

The image output unit 13 prints an image on paper (a sheet-likerecording medium) based on the received image data.

Processing units in the image processing unit 12 for performing varioustypes of image processing will be described below.

The scanner image processing unit 120 performs image processing such asshading correction and image area separation processing on RGB data.

The printer image processing unit 121 interprets commands included inthe PDL data to generate an intermediate code. Subsequently, a rasterimage processor (RIP) of the printer image processing unit 121 generatesRGB bitmap image data based on the intermediate code. The RIP not onlygenerates image data, but also generates (determines) attributeinformation for each pixel based on attribute information (hereinafterreferred to as an attribute) included in the commands. Referring to FIG.2, example attribute information includes a text attribute 20, abackground attribute 21, an image attribute 22, a thin line attribute23, and a graphic attribute 24. The background attribute 21 refers to awhite background including no objects.

When a text code and a font identifier are included in the PDL data,bitmap data of a character shape (glyph) corresponding to the text codeand font identifier is generated. Pixels representing this charactershape include the text attribute 20. When image data such as aphotograph is included in the PDL data, bitmap data of the photograph isgenerated. Pixels representing the photograph include the imageattribute 22. When vector data representing a thin line is included inthe PDL data, bitmap data of the thin line is generated. Pixelsrepresenting the thin line include the thin line attribute 23.

When outline information (vector data or point sequence data) isincluded in the PDL data, bitmap data of the graphic having an outlinerepresented by the outline information is generated. Pixels representingthe graphic include the graphic attribute 24. Therefore, when anoutlined text is included in the PDL data, bitmap data representing thetext is generated. Pixels in the text portion include a graphicattribute. This is because an outlined text is represented by theoutline information (vector data or point sequence data representingoutlines) of the text in the PDL data.

The printer image processing unit 121 can process PDL data as well asother image data represented by commands corresponding to eachindividual object (also referred to as an image object) constituting theimage.

A color processing unit 122 receives an RGB image from the scanner imageprocessing unit 120 or the printer image processing unit 121 andperforms color conversion processing on the RGB image to convert it intoCMYK (cyan, magenta, yellow, and black) bitmap image data (CMYK image).

An image correction processing unit 123 corrects pixel values (densityvalues) and attributes for the CMYK image. This processing will bedescribed in detail below with reference to FIG. 7.

A filter processing unit 124 performs processing such as edge emphasisby using pixel values and attributes corrected by the image correctionprocessing unit 123. The processed CMYK image is sent to an applicationamount control processing unit 125.

The application amount control processing unit 125 performs applicationamount control processing on the received CMYK image by using theattributes corrected by the image correction processing unit 123 andCMYK developing agents (toner) suitable for paper (a sheet-likerecording medium). The processed CMYK image is sent to a gammaprocessing unit 126.

The gamma processing unit 126 performs gamma processing on the receivedCMYK image by using the attributes corrected by the image correctionprocessing unit 123. The processed CMYK image is sent to a halftoneprocessing unit 127.

The halftone processing unit 127 performs dither processing on thereceived CMYK image by using the attribute information corrected by theimage correction processing unit 123. Error diffusion processing can beperformed in addition to dither processing. The processed CMYK image issent to a smoothing processing unit 128.

An effect arising from a case where the halftone processing unit 127uses the attributes corrected by the image correction processing unit123 will be described below. The halftone processing unit 127 performsoptimal dither processing for each attribute. More specifically, thehalftone processing unit 127 applies high screen ruling having a dotgrowth greater than or equal to 200 lines to a text attribute and a thinline attribute to make jaggies inconspicuous. The halftone processingunit 127 applies low screen ruling including a line growth ofapproximately 130 to 170 to a background attribute, an image attribute,and a graphic attribute to provide a resistance to color variation. Whenthe image correction processing unit 123 performs thickening processingon the object including a text attribute indicated by the left drawingillustrated in FIG. 3A, a CMYK image indicated by the right drawingillustrated in FIG. 3A is obtained. It is important that the attributeof the thickened portion (pixels of the expanded portion of the object)is corrected to a text attribute. Since the halftone processing unit 127applies high screen ruling based on a text attribute after thecorrection, jaggies at the thickened portion (pixels of the expandedportion of the object) becomes more inconspicuous than jaggies in a casewhere low screen ruling is applied.

The smoothing processing unit 128 performs processing (smoothingprocessing) for reducing jaggies due to halftone processing, on thereceived CMYK image. More specifically, as indicated by the left drawingillustrated in FIG. 4, increasing the pixel value of white pixels atedge portions of a text attribute object after dither processing fillsspaces by white pixels even after dither processing resulting in reducedjaggies, as indicated by the right drawing illustrated in FIG. 4. Thisprocessing is performed on a text attribute object, but is not performedon a graphic attribute object. The reason is as follows. If the pixelvalue of white pixels is increased to fill spaces by white pixels for agraphic attribute object, a thin white text appears blurring in suchimages as a thin outline character and a white line having a backgroundof a graphic attribute object.

<Thickening Processing by Image Correction Processing Unit>

The thickening processing by the image correction processing unit 123will be described below. The present exemplary embodiment will bedescribed below centering on a case where, as illustrated in FIG. 8, atext 801 outlined by an external application executed by an externalapparatus such as a PC is drawn in a graphic 802. However, the imageforming apparatus according to the present exemplary embodiment suitablyprocesses images in other cases. For example, a case where the text 801outlined by an external application is not in contact with any object(more specifically, a case where a graphic attribute text is drawnadjacently to pixels having a background attribute) is also suitablyprocessed by the image forming apparatus according to the presentexemplary embodiment. The outlined text refers to a text, of which theoutline is represented by a vector, which is converted into a graphic.An outlined text includes a graphic attribute. Although a CMYK image isdescribed below as an example, the processing according to the presentexemplary embodiment is also applicable to an RGB image.

<UI Screens>

Information settings related to thickening processing performed via theUI unit 17 will be described below with reference to FIGS. 6A and 6B.

Items set via the UI unit 17 will be described below. A user operationvia the UI unit 17 is notified to the CPU 16, information about itemsset by the operation (setting value of each item) is stored in thestorage unit 15. Then, the stored information is referenced by the imageprocessing unit 12 (image correction processing unit 123).

First, thickness adjustment on an object is set for each attribute. Asillustrated in FIG. 6A, the “Thickening and Thinning Settings” screenincludes a UI 172 for specifying a plurality of levels (−1, 0, and +1)indicating thinning, no adjustment, and thickening, respectively, foreach attribute. More specifically, when “+1” is specified for anattribute, the attribute is subjected to object width thickening.

A user presses a “detailed settings” button to set in detail howthickness adjustment is performed. Then, the detailed settings screenillustrated in FIG. 6B is displayed.

In the screen illustrated in FIG. 6B, the user sets the following threeitems: (1) color planes subjected to thickness adjustment, (2) directionin which thickness adjustment is performed, and (3) whether thicknessadjustment is performed on an object having a graphic background.

The first item will be described below. As indicated by a UI 174 (colorplanes to be corrected) illustrated in FIG. 6B, the user specifies “allcolors” or “black only” as color planes subjected to object thicknessadjustment. When “all colors” is specified, thickness adjustment isperformed on all the CMYK color planes constituting the object. When“all colors” is specified, a minimum pixel value (minimum density value)of “0” is set to each of the CMYK color planes as a threshold value tobe used in step S1732_2 illustrated in FIG. 7 (described below). When“black only” is specified, thickness adjustment is performed only on theK color plane constituting the object. When “black only” is specified, amaximum pixel value (maximum density value) of “255” is set for each ofthe CMY color planes as a threshold value to be used in step S1732_2illustrated in FIG. 7 (described below), and the minimum pixel value of“0” is set only for the K color plane.

The second item will be described below. The printing width of one pixelcan differ between the main and sub scanning directions depending onvariation of device characteristics. Therefore, as indicated by a UI 175(correction direction) illustrated in FIG. 6B, the user specifies“longitudinal” direction and/or “lateral” direction with respect to thepaper conveyance direction as a direction in which object thicknessadjustment is performed. According to the information specified in theUI 175, the number and arrangements of reference pixels with respect toa target pixel are determined as illustrated in FIGS. 10A to 10C in theprocessing window for object thickness adjustment.

FIG. 10A illustrates a processing window set when the user specifiesboth the longitudinal and lateral directions. In this processing window,three reference pixels are set adjacently to the target pixel in threedirections (right, bottom right, and bottom directions). FIG. 10Billustrates a processing window set when the user specifies only thelongitudinal direction. In this processing window, one reference pixelis set adjacently to the target pixel in one direction (bottomdirection). FIG. 10C illustrates a processing window set when the userspecifies only the lateral direction. In this processing window, onereference pixel is set adjacently to the target pixel in one direction(right direction). More specifically, referring to FIGS. 10A to 10C, theimage correction processing unit 123 sets as a target pixel either oneof at least two adjacent pixels included in image data and sets theother pixel as a reference pixel.

The pixel value of the target pixel is changed based on the pixel valuesof reference pixels by using the processing windows set as describedabove. More specifically, when the object positioned at the referencepixel differs from the object positioned at the target pixel, the objectpositioned at the reference pixel is thickened (expanded) toward thetarget pixel. More specifically, when the object having an attribute tobe subjected to thickening specified by the above-described UI 172 ispositioned at the reference pixel, and the object having an attributespecified as “background” is positioned at the target pixel, the pixelvalue of the target pixel is changed based on the pixel value of thereference pixel. The method for changing a pixel value will be describedbelow with reference to FIG. 7.

The third item will be described below. As indicated by a UI 176(background) illustrated in FIG. 6B, the user specifies whether toperform thickness adjustment on an object having a graphic background bypressing either one of a “provide background” or a “no background”button. The object having a graphic background refers to an object incontact with a graphic object (an object positioned inside or adjacentlyto a graphic object). When the “provide background” button is pressed, abackground attribute or a graphic attribute is specified as theattribute of the background of the object to be subjected to thicknessadjustment. When the “no background” is pressed, only a backgroundattribute is specified as the attribute of the background of the objectto be subjected to thickness adjustment.

When the user presses the OK button illustrated in FIG. 6B, informationset by the above-described UIs is stored in the storage unit 15.

<Flow of Thickening Processing>

The flow of the object thickening (expansion) processing to be performedby the image correction processing unit 123 will be described below withreference to FIG. 7. The following descriptions are on the premise thatthe settings illustrated in FIGS. 6A and 6B are made by the user,information about the settings is stored in the storage unit 15, andeach unit of the image correction processing unit 123 refers to thestored information. Although processing in one processing window will bedescribed below, the processing window is applied to each pixel of theCMYK image input to the image correction processing unit 123.

In step S1231, an attribute determination unit of the image correctionprocessing unit 123 performs the following determination about theattributes of the target and reference pixels in the processing window.The attribute determination unit determines whether the attribute of thetarget pixel is based on the user specification with the UI 176illustrated in FIG. 6B and the attribute of the reference pixel is anyone attribute specified as an attribute to be subjected to thickening inthe settings of the UI 172 by the user.

More specifically, in step S1231_1, when the user specifies “providebackground” with the UI 176, the attribute determination unit determineswhether the attribute of the target pixel is a background attribute or agraphic attribute. When the user specifies “no background” with the UI176, the attribute determination unit determines whether the attributeof the target pixel is a background attribute. When the attribute of thetarget pixel is determined to be the background or graphic attribute ina case where the user specifies “provide background”, and when theattribute of the target pixel is determined to be the background in acase where the user specifies “no background” (YES in step S1231_1), theprocessing proceeds to step S1231_2. When the attribute of the targetpixel is determined to be neither a background nor a graphic attributein a case where the user specifies “provide background”, and when theattribute of the target pixel is determined not to be the background ina case where the user specifies “no background” (NO in step S1231_1),the processing ends. In step S1231_2, the attribute determination unitdetermines which of the attributes set to “+1” in the settings of the UI172 by the user the attribute of the reference pixel is. According tothe settings illustrated in FIG. 6A, the attribute determination unitdetermines whether the attribute of the reference pixel is the text,thin line, or graphic attribute. When the attribute of the referencepixel is determined to be the text, thin line, or graphic attribute (YESin step S1231_2), the processing proceeds to step S1232. When theattribute of the reference pixel is determined to be neither the text,thin line, nor graphic attribute (NO in step S1231_2), the processingends. More specifically, when the reference pixel is an image attributepixel, the density value of the target pixel is left unchanged. In otherwords, an image attribute object is not subject to thickening. Thereason is as follows. An image attribute object is a photograph in manycases. Performing density value correction (change) (described below) ona photograph can reduce the clearness of the photograph. However,depending on the user settings illustrated in FIG. 6A, an imageattribute object can also be subjected to thickening.

In step S1232, a pixel value determination unit of the image correctionprocessing unit 123 performs the following processing for each of theCMYK color planes. (1) In step S1232_1, the pixel value determinationunit determines whether the pixel value of the target pixel is largerthan a predetermined threshold value. (2) In step S1232_2, the pixelvalue determination unit determines whether the pixel value of thereference pixel is larger than a threshold value (“0” or “255” asdescribed above) based on the setting of the UI 174 illustrated in FIG.6B. A series of determination processing in (1) and (2) will bedescribed below. When the two pixel values are determined to be greaterthan the respective threshold values (YES in steps S1232_1 and S1232_2)for all the color planes, the processing proceeds to step S1233. When atleast one of the two pixel values is determined not to be greater thanthe threshold value (NO in step S1232_1 or S1232_2) for at least onecolor plane, the processing ends.

When the predetermined threshold value to be used in determining thepixel value of the target pixel is the minimum pixel value (minimumdensity value) of “0”, the object can be thickened if the density of thebackground of the object (density value of the reference pixel) is notzero. When the predetermined threshold value is approximately a pixelvalue (density value) of “150”, the object can be thickened if thebackground of the object is dense to a certain extent. Although,according to the present exemplary embodiment, a designer of the imageforming apparatus sets the predetermined threshold value, the user canset the threshold value.

In step S1233, a density correction unit of the image correctionprocessing unit 123 corrects (changes), based on the pixel value of thereference pixel, the pixel value of the target pixel in the color plane.There are two different methods for correcting the pixel value: acorrection method 1 (step S1233_2) and a correction method 2 (stepS1233_3). Which of the correction methods 1 and 2 is to be used isdetermined by the settings of the UI 172 illustrated in FIG. 6A and thesetting of the UI 176 illustrated in FIG. 6B (step S1233_1). Morespecifically, in step S1233_1, the density correction unit determineswhether the same attribute is set to attributes to be subjected tothickening (attributes set to +1 by the user) specified by the settingsof the UI 172 and the attributes specified as a background by thesetting of the UI 176. In the example settings illustrated in FIGS. 6Aand 6B, a graphic attribute is included in both the attributes specifiedby the settings of the UI 172 (a text attribute, a thin line attribute,and a graphic attribute) and the attributes specified as a background bythe setting of the UI 176 (a background attribute and a graphicattribute). Therefore, the same attribute is determined to be set (YESin step S1233_1), and the processing proceeds to step S1233_2. In stepS1233_2, the density correction unit corrects the pixel value of thetarget pixel with the correction method 1. If the example settingsillustrated in FIG. 6A are left unchanged and “no background” isspecified in the example setting of the UI 176 illustrated in FIG. 6B,only a background attribute is specified as a background. In this case,the same attribute is determined not to be set (NO in step S1233_1), andthe processing proceeds to step S1233_3. In step S1233_3, the densitycorrection unit corrects the pixel value of the target pixel with thecorrection method 2.

The correction method 1 will be described in detail below. In thecorrection method 1, the density correction unit performs the followingprocessing (1) and (2) for each color plane. (1) The density correctionunit compares the pixel value of the reference pixel with the pixelvalue of the target pixel. (2) When the pixel value of the referencepixel is greater than the pixel value of the target pixel, the densitycorrection unit changes the pixel value of the target pixel to the pixelvalue of the reference pixel. When the pixel value of the referencepixel is not greater than the pixel value of the target pixel, thedensity correction unit leaves the pixel value of the target pixelunchanged. When processing is performed in this way, the pixel value ofthe target pixel becomes a mixture of the original pixel value of thetarget pixel for each color plane and the pixel value of the referencepixel for each color plane. More specifically, the density correctionunit expands the object positioned at the reference pixel toward theobject positioned at the target pixel to overlap the two objects witheach other. This enables acquiring the effect that the object on thereference pixel side is thickened toward the target pixel side.

If the above-described correction method 1 is used, the pixel value of atarget pixel 503_1 illustrated in FIG. 5A is changed to the pixel valueof a reference pixel 503_2 or 503_3 for the color planes in which thepixel value of the target pixel is less than the pixel value of thereference pixel. Performing such processing enables acquiring the pixelvalue of a target pixel 504, as illustrated in FIG. 5B. For example, asillustrated in FIG. 8, when the outlined text object 801 includes onlythe K color plane and the object 802 equivalent to the backgroundincludes only the C color plane, the target pixel 504 after change ofthe pixel value includes the K and C color planes. Which of thereference pixels 503_2 and 503_3 is to be used should be suitablydetermined. For example, a larger pixel value can be used.

With the correction method 2, the density correction unit changes thepixel value of the target pixel to the pixel value of the referencepixel for all the color planes. More specifically, the densitycorrection unit overwrites (replaces) the pixel value of the targetpixel with the pixel value of the reference pixel. This enables thetarget object to be thickened to become thick (expand) without beingmixed with the color of other objects. For example, the correctionmethod 2 is applied to a case where “text: +1, thin line: +1, graphic:0” is set in the UI 172 illustrated in FIG. 6A or a case where “nobackground” is set in the UI 176. When “provide background” is set inthe former case, the outlined text 801 in the graphic 802 illustrated inFIG. 8 becomes thick (expands) without being mixed with the color (Ccolor plane) of the graphic 802.

The correction method 1 is required in addition to the correction method2 for changing the pixel value of one object to the object pixel valueof the other object at the boundary between the objects because the sameattribute (graphic attribute) is included in the settings of the UI 172and 176. In such settings, the pixel value is also changed when graphicattribute objects are in contact with each other. However, since thedensity correction unit is unable to determine which of the objects isan outlined text, the correction method 1 is used to generate a mixedcolor of the two objects at the boundary thereof to adjust the thicknessof the objects.

As described above, the density correction unit suitably selects eitherof the two different correction methods, and changes the pixel value ofthe target pixel based on the pixel value of the reference pixel. Then,the processing proceeds to step S1234.

In step S1234, an attribute correction unit of the image correctionprocessing unit 123 corrects the attribute of the target pixel based onthe attribute of the reference pixel. For example, when the referencepixel has a text attribute and the target pixel has a graphic attribute,the attribute correction unit changes the target pixel to a textattribute.

According to the above-described processing flow illustrated in FIG. 7,an object of an attribute to be subjected to thickening can be thickenedboth in a case where the attribute of the target to be thickened differsfrom the adjacent attribute and a case where the attribute of the targetto be thickened is the same as the adjacent attribute. For example, evenin a case where a graphic attribute object is adjacent to a backgroundattribute pixel and in a case where a graphic attribute object isadjacent to a graphic attribute pixel, the object can be thickened. As aresult, it becomes possible not only to thicken an outlined textsurrounded by a background attribute, but also to thicken an outlinedtext included in a graphic.

In a case where a graphic attribute pixel is adjacent to a textattribute pixel, the density value of the graphic attribute pixel iscorrected (changed) based on the density value of the text attributepixel. The density value of the text attribute pixel is not corrected(changed) based on the density value of the graphic attribute pixel.This is because a graphic attribute pixel adjacent to a text attributepixel is assumed to be not an outlined text pixel, but an originallygraphic pixel such as a rectangle. In such a case, therefore, theattribute correction unit expands a text attribute object and does notexpand a graphic attribute object.

The above-described processing units in steps S1233 and S1234 can beintegrally formed as a correction unit (changing unit).

When the attribute of the target to be thickened is the same as theattribute of the background, a non-white object is thickened, whereas awhite object is thinned. Some users do not like thinning of a whiteobject. In this case, such a user can specify “no background” for thesetting of the UI 176 illustrated in FIG. 6B to enable differentiatingthe attribute of the target to be thickened from a background attribute,thus preventing a white object from being thinned. A graphic attributewithout a background can be thickened.

Although not described in the present exemplary embodiment, performingsimilar processing to the present exemplary embodiment enables thicknessadjustment even when an image object exists in an image attributeobject.

According to the present exemplary embodiment, the attributedetermination unit determines whether to perform thickening when theattribute of the target pixel is the same as the attributes of thereference pixel in the user settings via the UI unit 17. However,instead of referring to the settings in the UI unit 17, the attributedetermination unit can refer to an image to determine whether both thetarget and reference pixels include a graphic attribute. When both thetarget and reference pixels include a graphic attribute, the imagecorrection processing unit 123 corrects the pixel value of the targetpixel based on the pixel value of the reference pixel by using thecorrection method 1. When the target and reference pixels includedifferent attributes, the image correction processing unit 123 canreplace the pixel value of the target pixel with the pixel value of thereference pixel by using the correction method 2.

A second exemplary embodiment will be described below. According to thefirst exemplary embodiment, to thicken (expand) an object, the densitycorrection unit changes (replaced) the pixel value of the target pixelto (with) the pixel value of the reference pixel for the color planes ofthe target pixel having a smaller pixel value than the pixel value ofthe reference pixel. The method for mixing the colors of the target andreference pixels in this way will largely change the color of a portionto be thickened depending on the colors of the target and referencepixels. For example, at the boundary between the C and M color planes,the color of a thickened portion becomes deep blue.

The present exemplary embodiment will be described below centering on amethod for restricting color variation by performing thickeningadjustment only when the target pixel has low density and the referencepixel has high density. Descriptions of processing similar to theprocessing according to the first exemplary embodiment will be omitted.The present exemplary embodiment is characterized in the determinationin step S1232 and is similar in other steps to the first exemplaryembodiment. Therefore, only the difference from step S1232 in the firstexemplary embodiment will be described below.

In step S1232_1, the pixel value determination unit determines whetherthe target pixel is thin. When the pixel value of the target pixel isless than a predetermined value (thin) for all the color planes (YES instep S1232_1), the processing proceeds to step S1232_2. For example, thepredetermined value is a value indicating the intermediate density, suchas a pixel value of 128. When the pixel value of the target pixel islarger than the predetermined value for any one color plane (NO in stepS1232_1), the processing exits the flowchart.

In step S1232_2, the pixel value determination unit determines whetherthe pixel value of the reference pixel has high density. When the pixelvalue of the reference pixel is greater than a predetermined value(thick) for any one color plane (YES in step S1232_2), the processingproceeds to step S1233. When the pixel value of the reference pixel isless than the predetermined value (NO in step S1232_2) for all colorplanes, the processing exits this flowchart. When “all colors” isspecified by the setting of the UI 174, the predetermined value is apixel value of 150 indicating the intermediate density for each of theCMYK color planes. When “black only” is specified, the predeterminedvalue is a pixel value of 0 for each of the CMY color planes and a pixelvalue of 150 for the K color plane.

As described above, performing thickening adjustment only when thetarget pixel has low density and the reference pixel has high densityenables restricting color variation, thus restricting color variation ata thickened portion.

A third exemplary embodiment will be described below centering on amethod for restricting jaggies occurring when a text is outlined tobecome a graphic attribute text, depending on output conditions of anexternal application and a driver. In step S1234, the attributecorrection unit assigns a text attribute to a portion having undergonethickness adjustment, and the smoothing processing unit 128 reducesjaggies. The method for reducing jaggies in this step will be describedbelow. For processing identical to that according to the first and thesecond exemplary embodiments, redundant descriptions thereof will beomitted.

When a text attribute is output as it is as described above, halftoneprocessing for texts is performed by the halftone processing unit 127,and therefore the text is drawn through high dot screen ruling with 200or more lines. Further, the smoothing processing unit 128 performsprocessing for filling spaces on the dot screen at edge portions. Thisenables preventing jaggies from being conspicuous.

When a text attribute changes to a graphic attribute depending on outputconditions, halftone processing for graphics is performed by thehalftone processing unit 127, and therefore the text is drawn with lowscreen ruling having a line growth of about 130 to 170 lines. Since thesmoothing processing unit 128 does not perform smoothing processing on agraphic attribute because of the above-described reason, jaggies areconspicuous. This means that there is a large difference between theimage quality of a text output as a text attribute and the image qualityof a text changed to a graphic attribute. Jaggies caused by notperforming smoothing processing by the smoothing processing unit 128 areconspicuous in an object not having a graphic background and areinconspicuous in an object (text in a graphic) having a graphicbackground. A thin object having a graphic background can be blurred bythe processing of the smoothing processing unit 128.

According to the present exemplary embodiment, the attribute correctionunit leaves the attribute of a graphic attribute object having abackground of a graphic (graphic attribute object) unchanged. Theattribute correction unit changes (corrects) the attribute of a graphicattribute object not having a graphic background to a text attribute.This enables reducing the above-described image degradation due tojaggies.

In step S1234 illustrated in FIG. 7, the attribute correction unitaccording to the present exemplary embodiment performs the followingprocessing (steps S1234_1 and S1234_3) illustrated in FIG. 9.

In step S1234_1, the attribute correction unit determines whether thetarget and reference pixels have the same attribute. When the target andreference pixels are determined to have the same attribute (YES in stepS1234_1), the processing exits this flowchart. In this case, theattribute of the target pixel remains unchanged. As indicated in anexample illustrated in FIG. 3C, when the target and reference pixelshave the same attribute (when the target and reference pixels have agraphic attribute), the attribute of the portion where the object isthickened (expanded) remains unchanged.

When the target and reference pixels do not have the same attribute (NOin step S1234_1), the processing proceeds to step S1234_3.

In step S1234_3, when the target pixel includes a background attributeand the reference pixel has a text, a thin line, or a graphic attribute,the attribute correction unit changes the attribute of the target pixelto a text attribute. As indicated in an example illustrated in FIG. 3B,when the target and reference pixels include a specific combination ofattributes (when the target pixel has a background attribute and thereference pixel has a graphic attribute), the attribute of the portionwhere the object is thickened (expanded) is changed from the backgroundto a text attribute.

Similarly, in step S1234_3, when the target pixel includes a graphicattribute and the reference pixel includes a text, a thin line, or agraphic attribute, the attribute correction unit changes (replaces) theattribute of the target pixel to (with) the attribute of the referencepixel.

If the attribute of a pixel where jaggies are conspicuous is changed toa text attribute or a thin line attribute, the smoothing processing unit128 performs smoothing to enable reducing jaggies.

OTHER EMBODIMENTS

Embodiment(s) can also be realized by a computer of a system orapparatus that reads out and executes computer executable instructions(e.g., one or more programs) recorded on a storage medium (which mayalso be referred to more fully as a ‘non-transitory computer-readablestorage medium’) to perform the functions of one or more of theabove-described embodiment(s) and/or that includes one or more circuits(e.g., application specific integrated circuit (ASIC)) for performingthe functions of one or more of the above-described embodiment(s), andby a method performed by the computer of the system or apparatus by, forexample, reading out and executing the computer executable instructionsfrom the storage medium to perform the functions of one or more of theabove-described embodiment(s) and/or controlling the one or morecircuits to perform the functions of one or more of the above-describedembodiment(s). The computer may comprise one or more processors (e.g.,central processing unit (CPU), micro processing unit (MPU)) and mayinclude a network of separate computers or separate processors to readout and execute the computer executable instructions. The computerexecutable instructions may be provided to the computer, for example,from a network or the storage medium. The storage medium may include,for example, one or more of a hard disk, a random-access memory (RAM), aread only memory (ROM), a storage of distributed computing systems, anoptical disk (such as a compact disc (CD), digital versatile disc (DVD),or Blu-ray Disc (BD)™), a flash memory device, a memory card, and thelike.

While exemplary embodiments have been described, it is to be understoodthat the invention is not limited to the disclosed exemplaryembodiments. The scope of the following claims is to be accorded thebroadest interpretation so as to encompass all such modifications andequivalent structures and functions.

This application claims the benefit of Japanese Patent Application No.2016-012865, filed Jan. 26, 2016, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. A printing apparatus comprising: a reception unitconfigured to receive outline information representing an outline of acharacter; a generation unit configured to generate, using the outlineinformation, a bitmap including pixels corresponding to the character,the pixels being associated with a graphic attribute; a changing unitconfigured to refer an attribute associated with a pixel adjacent to oneof the pixels corresponding to the character, and to change a densityvalue of the adjacent pixel associated with the referred attribute beingdifferent from a graphic attribute and a character attribute to adensity which is based on a density value of the one pixel; and aprinting unit configured to print an image based on the bitmap after thechange.
 2. The printing apparatus according to claim 1, furthercomprising: an attribute changing unit configured to change an attributeassociated with the adjacent pixel to a character attribute; and ascreen unit configured to perform screen processing with a first screenruling on a pixel associated with a graphic attribute and to performscreen processing with a second screen ruling higher than the firstscreen ruling on a pixel associated with a character attribute.
 3. Theprinting apparatus according to claim 1, wherein the outline informationis point sequence data representing a shape of the outline.
 4. Aprinting apparatus for processing image data of pixels including acharacter outlined by an external apparatus, the printing apparatuscomprising: a changing unit configured to change a density value of apixel associated with a background attribute adjacent to a pixel of theoutlined character associated with a graphic attribute to a densityvalue of the pixel associated with a graphic attribute; and a printingunit configured to print the changed image data.
 5. The printingapparatus according to claim 4, further comprising: a setting unitconfigured to set two adjacent pixels included in the image data as atarget pixel and a reference pixel; and a determination unit configuredto determine an attribute for each of the target and reference pixels,wherein, based on the determination by the determination unit, thechanging unit determines whether to change a density value of the targetpixel based on a density value of the reference pixel, and wherein,based on the determination indicating that the attribute of the targetpixel is a background attribute and that the attribute of the referencepixel is a graphic attribute, the changing unit changes the densityvalue of the target pixel based on the density value of the referencepixel.
 6. The printing apparatus according to claim 4, furthercomprising: a reception unit configured to receive PDL data includingthe outlined character from the external apparatus; and a generationunit configured to generate the image data based on the PDL data,wherein a graphic shape and an outlined character are represented byoutline information in PDL data, and wherein a character not outlined isrepresented by a character code in PDL data, wherein, in the generation,the generation unit associates an attribute with each pixel included inthe image data, and wherein the generation unit associates pixels of agraphic portion and a character portion represented by outlineinformation with a graphic attribute, associates pixels of a characterportion represented by a character code with a character attribute, andassociates pixels of a portion including no object with a backgroundattribute.
 7. The printing apparatus according to claim 5, wherein,based on the determination by the determination unit indicating that theattribute of the target pixel is a graphic attribute and that theattribute of the reference pixel is a character attribute, the changingunit changes the density value of the target pixel based on the densityvalue of the reference pixel, wherein, based on the determination by thedetermination unit indicating that the attribute of the target pixel isa character attribute and that the attribute of the reference pixel is agraphic attribute, the changing unit leaves the density value of thetarget pixel unchanged based on the density value of the referencepixel, and wherein, based on the determination by the determination unitindicating that the attribute of the target pixel is a graphic attributeand that the attribute of the reference pixel is a graphic attribute,the changing unit changes the density value of the target pixel based onthe density value of the reference pixel.
 8. The printing apparatusaccording to claim 5, wherein based on the determination by thedetermination unit indicating that the attribute of the target pixel isa background attribute and that the attribute of the reference pixel isa character attribute, the changing unit changes the density value ofthe target pixel based on the density value of the reference pixel. 9.The printing apparatus according to claim 5, further comprising a usersetting unit configured to, based on a user instruction, set whether toinstruct the changing unit to change the density value of the targetpixel when the target pixel is associated with a graphic attribute,wherein, based on the setting by the user setting unit instructs thechanging unit to change the density value of the target pixel when thetarget pixel is associated with a graphic attribute, the changing unitchanges the density value of the target pixel determined to have agraphic attribute based on the density value of the reference pixel, andwherein, based the setting by the user setting unit instructs thechanging unit to leave the density value of the target pixel unchangedwhen the target pixel is associated with a graphic attribute, thechanging unit leaves the density value of the target pixel determined tohave a graphic attribute unchanged based on the density value of thereference pixel.
 10. The printing apparatus according to claim 5.wherein, for a color plane in which the density value of the referencepixel is greater than the density value of the target pixel, thechanging unit changes the density value of the target pixel based on thedensity value of the reference pixel, and wherein, for a color plane inwhich the density value of the reference pixel is not greater than thedensity value of the target pixel, the changing unit leaves the densityvalue of the target pixel unchanged.
 11. The printing apparatusaccording to claim 5, wherein, based on the attribute of the referencepixel, the changing unit changes the attribute of the target pixel ofwhich the density value is to be changed.
 12. The printing apparatusaccording to claim 11, wherein, based on a combination of the attributesof the target and reference pixels, the changing unit changes theattribute of the target pixel of which the density value is to bechanged to a character attribute.
 13. The printing apparatus accordingto claim 12 further comprising a halftone processing unit configured toperform dither processing based on the changed attribute on the targetpixel of which the density value and the attribute are changed by thechanging unit.
 14. The printing apparatus according to claim 12 furthercomprising a smoothing processing unit configured to perform smoothingprocessing based on the changed character attribute on the target pixelof which the density value and the attribute are changed by the changingunit.
 15. A printing method for processing image data of pixelsincluding a character outlined by an external apparatus, the printingmethod comprising: changing a density value of a pixel associated with abackground attribute adjacent to a pixel of the outlined characterassociated with a graphic attribute based on a density value of thepixel associated with a graphic attribute; and printing the changedimage data.
 16. The printing method according to claim 15, furthercomprising: setting two adjacent pixels included in the image data as atarget pixel and a reference pixel; and determining an attribute foreach of the target and reference pixels, wherein, based on thedetermination by the determining, whether to change a density value ofthe target pixel based on a density value of the reference pixel isdetermined, and wherein, based on the determination by the determiningindicating that the attribute of the target pixel is a backgroundattribute and that the attribute of the reference pixel is a graphicattribute, the density value of the target pixel is changed based on thedensity value of the reference pixel.
 17. The printing method accordingto claim 16, wherein, based on the determination by the determiningindicating that the attribute of the target pixel is a graphic attributeand that the attribute of the reference pixel is a character attribute,the density value of the target pixel is changed based on the densityvalue of the reference pixel, wherein, based on the determination by thedetermining indicating that the attribute of the target pixel is acharacter attribute and that the attribute of the reference pixel is agraphic attribute, the density value of the target pixel is leftunchanged based on the density value of the reference pixel, andwherein, based on the determination by the determining indicating thatthe attribute of the target pixel is a graphic attribute and that theattribute of the reference pixel is a graphic attribute, the densityvalue of the target pixel is changed based on the density value of thereference pixel.